摘要
制备了用作直接甲醇燃料电池的碳载Pt-Fe(Pt-Fe/C)阴极催化剂,X射线能量色散谱(EDX)、X射线衍射谱和电化学测量的结果表明,在Pt-Fe/C催化剂中,Fe以3种形式存在.质量分数大约为20%的Fe进入Pt的晶格,形成Pt-Fe合金,质量分数大约为80%的Fe没有进入Pt的晶格而以Fe和Fe2O3的形式单独存在.该催化剂经酸处理后,非合金化Fe和Fe2O3被溶解,而使Pt-Fe/C催化剂的电化学活性比表面积要比未经酸处理前的增加约30%左右,导致Pt-Fe/C催化剂对氧还原的电催化活性优于未经酸处理前的Pt-Fe/C催化剂.研究结果表明,Pt-Fe/C催化剂的电化学活性比表面积对氧还原的电催化活性起重要的作用,另外,只有与Pt形成合金的Fe能提高Pt对氧还原的电催化活性,而非合金化的Fe对Pt催化剂对氧还原的电催化活性基本没有影响.
In this paper, the carbon supported Pt-Fe（Pt-Fe/C） cathodic catalyst in the direct methanol fuel cell was prepared. The results of the energy dispersive X-ray （EDX） analysis, X-ray reflection spectroscopy （XRD） and electrochemical measurements indicate that in the Pt-Fe/C catalyst, Fe exists as the three forms. About 20% （ mass fraction） Fe enters the crystal lattice of Pt, forming the alloy with Pt. About 80% （ mass fraction） Fe does not enter the crystal lattice of Pt and exists as Fe and Fe203. After the Pt-Fe/C catalyst being treated with acid , non-alloying Fe and FeE O3 in the catalyst are dissolved. Therefore, the electrochemically active specific surface area of the Pt-Fe particles in the Pt-Fe/C catalyst after the acid treatment is 30% larger than that of the Pt-Fe/C catalyst before the acid treatment. Thus, the electrocatalytic activity of the Pt-Fe/C catalyst after the acid treatment for the oxygen reduction is higher than that of the Pt-Fe/C catalyst before the acid treatment. It illustrates that the electrochemically active specific surface area of the Pt-Fe particles in the Pt-Fe/C catalyst can significantly affects the electrocatalytic activity of the Pt-Fe/C catalyst for the oxygen reduction. In addition, it also demonstrates that only alloying Fe can increase the electrocatalytic activity of the Pt for the oxygen reduction and non-alloying Fe has no such effect.
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
2007年第4期743-746,共4页
Chemical Journal of Chinese Universities
基金
国家自然科学基金(批准号:20433060
20573057
20573029)
江苏省高校自然科学基金(批准号:05KJB150061)资助.
关键词
碳载Pt-Fe催化剂
氧还原
电化学活性比表面积
电催化活性
Carbon supported Pt-Fe catalyst
Oxygen reduction
Electrochemically active specific surface area
Electrocatalytic activity
